# Relationship history for MSHA mine 3503741

Current hierarchy: **George J  Williamson → C J Excavating → Screen Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** George J  Williamson → Screen Plant; 1999-10-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** C J Excavating → Screen Plant; 2010-02-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** George J  Williamson → C J Excavating; 2010-02-23 to current/open; source msha-controller-operator-history